Surface Hardening Method in Roller Hearth Furnace.

surface hardening is quite evident when we want to harden it often it is not possible to get uniform properties from surface to the core, because of the limitation of the cooling rate that we adopt.

Even if we quench, if the dimension is large, the code will make depending on the dimension of the job the core may cool very slowly you may have a totally different structure and properties at the core whereas you may have extremely hard structure at the surface.

And in surface hardening, we actually try to exploit this feature. what are the types of component where we need surface hardening? some will look at some common methods of surface hardening, we will talk about induction hardening, we will talk about that a carburization process, case carburizing, we will talk about post carburization heat treatment case and core refining.

we will also look at the residual stress pattern that is likely to develop as a result of surface hardening. It is beneficial and their is another process of surface hardening call nitriding. Composition of the material what the material consists of whether it is a pure metal, or it's an alloy, what are the alloying elements added. And how do we process; whether it is cold rolled, or whether it is annealed, or whether it is cold rolled and recrystallized structure or whether it has been given some special heat treatment, or some thermomechanical processing, that will affect these properties or whenever we select a material, it has it's with a specific objective it has to perform well in surface. These all terms used in surface hardening.

Now this performance criteria may vary for component to component, for certain component we will look at certain specific properties. Suppose if we are selecting a material for cutting tool or a hacksaw. what we will look for whether the material is extremely hard, can be hardened so that it can cut most material.

So in that case obvious choice will be say suppose we say that plain carbon steel because hacksaw is quite thin. You can quench a plain carbon steel so having a high carbon content, and you can get fully martensitic structure give it a low temperature tempering, and it will have a very high hardness, close to our Rc64 and with this you will be able to cut most metallic materials and many other nonmetallic material as well. so, here the performance you know the processing is actually apart from the making the sheet of this amine thin sheets from which by thermo mechanical processing from which hacksaw will be made.Another important processing is heat treatment. hence there are different furnaces where case hardening can be performed like Sealed Quench Furnace, Roller Hearth Furnace, Chamber Furnace, Pit Furnace etc.

Now here are some examples, also we go through this lecture and in fact when we look at a real component it always has a particular dimension and very often these dimensions are quite large so, one of the common structural component that you may have seen is I beams say it is used in bridges it is used in multi-story a construction of multi-story buildings; and there you will find the section has different dimension in different zones.

I'm R.Hemalatha a writer here, working in the manufacturing industry with experience of more than 10+ years. I enjoy writing a content that require some creative thinking and editing content which is original one.